ethers.js/packages/providers/lib/fallback-provider.js
2020-02-04 01:06:47 -05:00

504 lines
24 KiB
JavaScript

"use strict";
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
return extendStatics(d, b);
};
return function (d, b) {
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
var __generator = (this && this.__generator) || function (thisArg, body) {
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}
};
Object.defineProperty(exports, "__esModule", { value: true });
var abstract_provider_1 = require("@ethersproject/abstract-provider");
var random_1 = require("@ethersproject/random");
var properties_1 = require("@ethersproject/properties");
var bignumber_1 = require("@ethersproject/bignumber");
var logger_1 = require("@ethersproject/logger");
var _version_1 = require("./_version");
var logger = new logger_1.Logger(_version_1.version);
var base_provider_1 = require("./base-provider");
function now() { return (new Date()).getTime(); }
// Returns to network as long as all agree, or null if any is null.
// Throws an error if any two networks do not match.
function checkNetworks(networks) {
var result = null;
for (var i = 0; i < networks.length; i++) {
var network = networks[i];
// Null! We do not know our network; bail.
if (network == null) {
return null;
}
if (result) {
// Make sure the network matches the previous networks
if (!(result.name === network.name && result.chainId === network.chainId &&
((result.ensAddress === network.ensAddress) || (result.ensAddress == null && network.ensAddress == null)))) {
logger.throwArgumentError("provider mismatch", "networks", networks);
}
}
else {
result = network;
}
}
return result;
}
function median(values) {
values = values.slice().sort();
var middle = Math.floor(values.length / 2);
// Odd length; take the middle
if (values.length % 2) {
return values[middle];
}
// Even length; take the average of the two middle
var a = values[middle - 1], b = values[middle];
return (a + b) / 2;
}
function serialize(value) {
if (value === null) {
return "null";
}
else if (typeof (value) === "number" || typeof (value) === "boolean") {
return JSON.stringify(value);
}
else if (typeof (value) === "string") {
return value;
}
else if (bignumber_1.BigNumber.isBigNumber(value)) {
return value.toString();
}
else if (Array.isArray(value)) {
return JSON.stringify(value.map(function (i) { return serialize(i); }));
}
else if (typeof (value) === "object") {
var keys = Object.keys(value);
keys.sort();
return "{" + keys.map(function (key) {
var v = value[key];
if (typeof (v) === "function") {
v = "[function]";
}
else {
v = serialize(v);
}
return JSON.stringify(key) + ":" + v;
}).join(",") + "}";
}
throw new Error("unknown value type: " + typeof (value));
}
// Next request ID to use for emitting debug info
var nextRid = 1;
;
// Returns a promise that delays for duration
function stall(duration) {
return new Promise(function (resolve) {
var timer = setTimeout(resolve, duration);
if (timer.unref) {
timer.unref();
}
});
}
;
function exposeDebugConfig(config, now) {
var result = {
provider: config.provider,
weight: config.weight
};
if (config.start) {
result.start = config.start;
}
if (now) {
result.duration = (now - config.start);
}
if (config.done) {
if (config.error) {
result.error = config.error;
}
else {
result.result = config.result || null;
}
}
return result;
}
function normalizedTally(normalize, quorum) {
return function (configs) {
// Count the votes for each result
var tally = {};
configs.forEach(function (c) {
var value = normalize(c.result);
if (!tally[value]) {
tally[value] = { count: 0, result: c.result };
}
tally[value].count++;
});
// Check for a quorum on any given result
var keys = Object.keys(tally);
for (var i = 0; i < keys.length; i++) {
var check = tally[keys[i]];
if (check.count >= quorum) {
return check.result;
}
}
// No quroum
return undefined;
};
}
function getProcessFunc(provider, method, params) {
var normalize = serialize;
switch (method) {
case "getBlockNumber":
// Return the median value, unless there is (median + 1) is also
// present, in which case that is probably true and the median
// is going to be stale soon. In the event of a malicious node,
// the lie will be true soon enough.
return function (configs) {
var values = configs.map(function (c) { return c.result; });
// Get the median block number
var blockNumber = Math.ceil(median(configs.map(function (c) { return c.result; })));
// If the next block height is present, its prolly safe to use
if (values.indexOf(blockNumber + 1) >= 0) {
blockNumber++;
}
// Don't ever roll back the blockNumber
if (blockNumber >= provider._highestBlockNumber) {
provider._highestBlockNumber = blockNumber;
}
return provider._highestBlockNumber;
};
case "getGasPrice":
// Return the middle (round index up) value, similar to median
// but do not average even entries and choose the higher.
// Malicious actors must compromise 50% of the nodes to lie.
return function (configs) {
var values = configs.map(function (c) { return c.result; });
values.sort();
return values[Math.floor(values.length / 2)];
};
case "getEtherPrice":
// Returns the median price. Malicious actors must compromise at
// least 50% of the nodes to lie (in a meaningful way).
return function (configs) {
return median(configs.map(function (c) { return c.result; }));
};
// No additional normalizing required; serialize is enough
case "getBalance":
case "getTransactionCount":
case "getCode":
case "getStorageAt":
case "call":
case "estimateGas":
case "getLogs":
break;
// We drop the confirmations from transactions as it is approximate
case "getTransaction":
case "getTransactionReceipt":
normalize = function (tx) {
if (tx == null) {
return null;
}
tx = properties_1.shallowCopy(tx);
tx.confirmations = -1;
return serialize(tx);
};
break;
// We drop the confirmations from transactions as it is approximate
case "getBlock":
// We drop the confirmations from transactions as it is approximate
if (params.includeTransactions) {
normalize = function (block) {
if (block == null) {
return null;
}
block = properties_1.shallowCopy(block);
block.transactions = block.transactions.map(function (tx) {
tx = properties_1.shallowCopy(tx);
tx.confirmations = -1;
return tx;
});
return serialize(block);
};
}
else {
normalize = function (block) {
if (block == null) {
return null;
}
return serialize(block);
};
}
break;
default:
throw new Error("unknown method: " + method);
}
// Return the result if and only if the expected quorum is
// satisfied and agreed upon for the final result.
return normalizedTally(normalize, provider.quorum);
}
function getRunner(provider, method, params) {
switch (method) {
case "getBlockNumber":
case "getGasPrice":
return provider[method]();
case "getEtherPrice":
if (provider.getEtherPrice) {
return provider.getEtherPrice();
}
break;
case "getBalance":
case "getTransactionCount":
case "getCode":
return provider[method](params.address, params.blockTag || "latest");
case "getStorageAt":
return provider.getStorageAt(params.address, params.position, params.blockTag || "latest");
case "getBlock":
return provider[(params.includeTransactions ? "getBlockWithTransactions" : "getBlock")](params.blockTag || params.blockHash);
case "call":
case "estimateGas":
return provider[method](params.transaction);
case "getTransaction":
case "getTransactionReceipt":
return provider[method](params.transactionHash);
case "getLogs":
return provider.getLogs(params.filter);
}
return logger.throwError("unknown method error", logger_1.Logger.errors.UNKNOWN_ERROR, {
method: method,
params: params
});
}
var FallbackProvider = /** @class */ (function (_super) {
__extends(FallbackProvider, _super);
function FallbackProvider(providers, quorum) {
var _newTarget = this.constructor;
var _this = this;
logger.checkNew(_newTarget, FallbackProvider);
if (providers.length === 0) {
logger.throwArgumentError("missing providers", "providers", providers);
}
var providerConfigs = providers.map(function (configOrProvider, index) {
if (abstract_provider_1.Provider.isProvider(configOrProvider)) {
return Object.freeze({ provider: configOrProvider, weight: 1, stallTimeout: 750, priority: 1 });
}
var config = properties_1.shallowCopy(configOrProvider);
if (config.priority == null) {
config.priority = 1;
}
if (config.stallTimeout == null) {
config.stallTimeout = 750;
}
if (config.weight == null) {
config.weight = 1;
}
var weight = config.weight;
if (weight % 1 || weight > 512 || weight < 1) {
logger.throwArgumentError("invalid weight; must be integer in [1, 512]", "providers[" + index + "].weight", weight);
}
return Object.freeze(config);
});
var total = providerConfigs.reduce(function (accum, c) { return (accum + c.weight); }, 0);
if (quorum == null) {
quorum = total / 2;
}
else if (quorum > total) {
logger.throwArgumentError("quorum will always fail; larger than total weight", "quorum", quorum);
}
// All networks are ready, we can know the network for certain
var network = checkNetworks(providerConfigs.map(function (c) { return (c.provider).network; }));
if (network) {
_this = _super.call(this, network) || this;
}
else {
// The network won't be known until all child providers know
var ready = Promise.all(providerConfigs.map(function (c) { return c.provider.getNetwork(); })).then(function (networks) {
return checkNetworks(networks);
});
_this = _super.call(this, ready) || this;
}
// Preserve a copy, so we do not get mutated
properties_1.defineReadOnly(_this, "providerConfigs", Object.freeze(providerConfigs));
properties_1.defineReadOnly(_this, "quorum", quorum);
_this._highestBlockNumber = -1;
return _this;
}
FallbackProvider.prototype.perform = function (method, params) {
return __awaiter(this, void 0, void 0, function () {
var processFunc, configs, i, _loop_1, this_1, state_1;
var _this = this;
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
// Sending transactions is special; always broadcast it to all backends
if (method === "sendTransaction") {
return [2 /*return*/, Promise.all(this.providerConfigs.map(function (c) {
return c.provider.sendTransaction(params.signedTransaction).then(function (result) {
return result.hash;
}, function (error) {
return error;
});
})).then(function (results) {
// Any success is good enough (other errors are likely "already seen" errors
for (var i_1 = 0; i_1 < results.length; i_1++) {
var result = results[i_1];
if (typeof (result) === "string") {
return result;
}
}
// They were all an error; pick the first error
return Promise.reject(results[0].error);
})];
}
processFunc = getProcessFunc(this, method, params);
configs = random_1.shuffled(this.providerConfigs.map(function (c) { return properties_1.shallowCopy(c); }));
configs.sort(function (a, b) { return (a.priority - b.priority); });
i = 0;
_loop_1 = function () {
var t0, inflightWeight, _loop_2, waiting, results, result;
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
t0 = now();
inflightWeight = configs.filter(function (c) { return (c.runner && ((t0 - c.start) < c.stallTimeout)); })
.reduce(function (accum, c) { return (accum + c.weight); }, 0);
_loop_2 = function () {
var config = configs[i++];
var rid = nextRid++;
config.start = now();
config.staller = stall(config.stallTimeout).then(function () { config.staller = null; });
config.runner = getRunner(config.provider, method, params).then(function (result) {
config.done = true;
config.result = result;
if (_this.listenerCount("debug")) {
_this.emit("debug", {
action: "request",
rid: rid,
backend: exposeDebugConfig(config, now()),
request: { method: method, params: properties_1.deepCopy(params) },
provider: _this
});
}
}, function (error) {
config.done = true;
config.error = error;
if (_this.listenerCount("debug")) {
_this.emit("debug", {
action: "request",
rid: rid,
backend: exposeDebugConfig(config, now()),
request: { method: method, params: properties_1.deepCopy(params) },
provider: _this
});
}
});
//running.push(config);
if (this_1.listenerCount("debug")) {
this_1.emit("debug", {
action: "request",
rid: rid,
backend: exposeDebugConfig(config, null),
request: { method: method, params: properties_1.deepCopy(params) },
provider: this_1
});
}
inflightWeight += config.weight;
};
// Start running enough to meet quorum
while (inflightWeight < this_1.quorum && i < configs.length) {
_loop_2();
}
waiting = [];
configs.forEach(function (c) {
if (c.done || !c.runner) {
return;
}
waiting.push(c.runner);
if (c.staller) {
waiting.push(c.staller);
}
});
if (!waiting.length) return [3 /*break*/, 2];
return [4 /*yield*/, Promise.race(waiting)];
case 1:
_a.sent();
_a.label = 2;
case 2:
results = configs.filter(function (c) { return (c.done && c.error == null); });
if (results.length >= this_1.quorum) {
result = processFunc(results);
if (result !== undefined) {
return [2 /*return*/, { value: result }];
}
}
// All configs have run to completion; we will never get more data
if (configs.filter(function (c) { return !c.done; }).length === 0) {
return [2 /*return*/, "break"];
}
return [2 /*return*/];
}
});
};
this_1 = this;
_a.label = 1;
case 1:
if (!true) return [3 /*break*/, 3];
return [5 /*yield**/, _loop_1()];
case 2:
state_1 = _a.sent();
if (typeof state_1 === "object")
return [2 /*return*/, state_1.value];
if (state_1 === "break")
return [3 /*break*/, 3];
return [3 /*break*/, 1];
case 3: return [2 /*return*/, logger.throwError("failed to meet quorum", logger_1.Logger.errors.SERVER_ERROR, {
method: method,
params: params,
//results: configs.map((c) => c.result),
//errors: configs.map((c) => c.error),
results: configs.map(function (c) { return exposeDebugConfig(c); }),
provider: this
})];
}
});
});
};
return FallbackProvider;
}(base_provider_1.BaseProvider));
exports.FallbackProvider = FallbackProvider;